Mailchimp API send campaign - php

Question

I have written a custom Drupal 8 module that will send article notifications to our Mailchimp subscribers.
Problem
Currently, the module loops over each of the article 'tags' and sends out a separate campaign for each. Consequently, if someone is subscribed two of an article's tags, they will receive two emails.
Solution
Instead, I'd like each person to receive a maximum of one email notification. I think that the best way to achieve this is to create a dynamic segment. Similar to the query posted here. However, I have been getting various errors, and can't find much help here and here.
Code
<?php
function mailchimp_notification_process(EntityInterface $node)
{
global $base_url;
$settings = Settings::get('mailchimp_audience');
$content = (object) array(
'subject_line' => 'XXX',
'title' => 'Notification',
'from_name' => 'XXX',
'reply_to' => 'noreply#gmail.com'
);
$template_content = [
'html' => [
'value' => '<table align="center" border="0" cellpadding="0" cellspacing="0" height="100%" width="100%" id="bodyTable">email content removed for brevity</table>',
'format' => 'mailchimp_campaign'
]
];
$mc_campaign = mailchimp_get_api_object('MailchimpCampaigns');
$lists = mailchimp_campaign_get_list_segments($settings, NULL);
if (
$node->isPublished() &&
($node->bundle() == 'article' || $node->bundle() == 'resource') &&
$node->field_send_notification->getString() == 1 &&
isset($node->field_send_notification_to->entity)
) {
$all_tags = [];
// loop over each of the loops to send notifications to
foreach ($node->field_send_notification_to as $category) {
$tags = array_filter($lists, function ($list) use ($category) {
return $list->name == $category->entity->getName();
});
if ($tags && is_array($tags)) {
$tags = reset($tags);
array_push($all_tags, $tags->id);
\Drupal::logger('mailchimp_notification')->notice('all_tags: ' . json_encode($all_tags));
}
}
$recipients = (object) [
'list_id' => $settings,
'segment_opts' => [
'match' => 'all',
'conditions' => [
[
'condition_type' => 'Tags',
'field' => 'tags-123',
'op' => 'interestcontainsall',
'value' => $all_tags,
]
]
]
];
\Drupal::logger('mailchimp_notification')->notice('recipients: ' . json_encode($recipients));
$campaign_id = mailchimp_campaign_save_campaign($template_content, $recipients, $content, "", "");
if ($campaign_id) {
$mc_campaign->send($campaign_id);
}
}
}